Epstein-Barr Virus, Infectious Mononucleosis

Key Features

Essentials of Diagnosis

• Prolonged fever

• Exudative pharyngitis

• Generalized adenopathy

• Hepatosplenomegaly

• Atypical lymphocytes

• Heterophil antibodies

General Considerations

• Mononucleosis is the most characteristic syndrome produced by EBV infection

• Young children infected with EBV have either no symptoms or a mild nonspecific febrile illness

• In older patients, EBV infection is more likely to produce the typical features of the mononucleosis syndrome

• EBV is acquired readily from asymptomatic carriers and from recently ill patients

• Young children are infected from the saliva of playmates and family members

• Adolescents may be infected through sexual activity

• EBV can also be transmitted by blood transfusion and organ transplantation

Clinical Findings

Symptoms and Signs

• Incubation period of 1–2 months

• A 2- to 3-day prodrome of malaise and anorexia yields, abruptly or insidiously, to a febrile illness with temperatures exceeding 39°C

• Lymph nodes are enlarged, firm, and mildly tender

• Rash is present in 5% of patients

  • Can be macular, scarlatiniform, or urticarial

  • Almost universal in patients taking penicillin or ampicillin

• Soft palate petechiae and eyelid edema are also observed

Differential Diagnosis

• Group A streptococcal infection

• Bacterial infection

• Severe primary herpes simplex pharyngitis

• Adenoviruses

• Serum sickness–like drug reactions and leukemia

• Cytomegalovirus mononucleosis

Diagnosis

• Leukopenia may occur early, but an atypical lymphocytosis (comprising over 10% of the total leukocytes at some time in the illness) is most notable

• Hematologic changes may not be seen until the third week of illness and may be entirely absent in some EBV syndromes (eg, neurologic)

• Heterophile antibodies

  • Appear in over 90% of older patients with mononucleosis, but in less than 50% of children younger than age 5 years

  • May not be detectable until the second week of illness

  • May persist for up to 12 months after recovery

  • Rapid screening tests (slide agglutination) are usually positive if the titer is significant

  • Positive result strongly suggests but does not prove EBV infection

• Acute EBV infection is established by detecting IgM antibody to the viral capsid antigen (VCA) or by detecting a fourfold or greater change of IgG anti-VCA titers

• Detection of EBV DNA is the method of choice for the diagnosis of CNS and ocular infections

Treatment

• Bed rest may be necessary in severe cases

• Acetaminophen controls high fever

• Potential airway obstruction due to swollen pharyngeal lymphoid tissue responds rapidly to systemic corticosteroids

• Acyclovir, valacyclovir, penciclovir, ganciclovir, and foscarnet are indicated for chronic active EBV

Outcome

Follow-Up

• Patients with splenic enlargement should avoid contact sports for 6–8 weeks

Complications

• Splenic rupture is rare, usually following significant trauma

• Hematologic complications, including hemolytic anemia, thrombocytopenia, and neutropenia, are more ...